Seat with a separately adjustable back rest and seat portion and an adjustable seat depth

ABSTRACT

A seat including a seat portion and a back rest both pivotable about a hinge pin ( 12 ). The hinge includes, on either side of the seat, a rotary back rest holder ( 10 ) having the hinge pin ( 12 ) extending therethrough, wherein the back rest holder is rigidly connected to the back rest and defines an attachment point ( 13 ) for a gas spring ( 6 ), as well as a slidable seat portion holder ( 11 ) having the hinge pin ( 12 ) extending therethrough, wherein the seat portion holder defines a further attachment point for the gas spring ( 6 ), and the seat portion holder ( 11 ) is slidably mounted relative to a member ( 9 ) rigidly connected to the seat portion and selectively lockable in a predetermined position relative thereto, whereby the seat depth is adjustable.

Seat with a separately adjustable back rest and seat portion and anadjustable seat depth.

The present invention relates to a seat of the type comprising a seatportion and a back rest, hinged to one another about an axis ofrotation.

More specifically, the present invention relates to a seat of theabovementioned type in which said hinging is achieved in the form of apair of means located on either side of the seat about a plane ofsymmetry passing through the back rest and the seat portion, each ofsaid means consisting of, on the one hand, a first element, forming aback rest rotation support, through which said axis of rotation passesand one end of which is integral with said back rest, and, on the otherhand, a second element.

A seat meeting this definition is known from US patent applicationUS2003/0011226 A1. It consists of a car seat comprising an invertedU-shaped part as a back rest structure 14 and a frame as a seat portionstructure 10, said frame being mounted so as to slide on a support 86.Each free end of the U-shaped part constitutes what was referred toabove as a first element, and the second element of the hinge system isa part integral with the frame 10, in such a way that the second elementis the seat portion frame itself. The ends of the U-shaped part areinserted in a slot made in the seat portion frame 10 in such a way that,when the seat portion structure slides, the back rest structure can onlyfollow.

No means are provided for adjusting the depth of the seat portion andany such adjustment is entirely impossible owing to the fact that theback rest structure is inserted in the seat portion structure.

However, an important factor in the user's comfort is that the depth ofthe seat portion be adapted to his size. For example, it is just asuncomfortable for a tall person whose thighs jut out to some extent overthe front of the seat portion as for a short person whose legs do nottouch the floor when he is sitting back in the seat.

The invention proposes a novel solution to this problem by combining thehinging of the back rest/seat with the adjustment of the depth of theseat portion.

To this end, the invention relates to a seat of the abovementioned type,characterized in that said second element is a part which is

-   -   separate from the seat portion,    -   integral with said first element via said axis of rotation which        passes through said second element near one of its ends and said        first element,    -   mounted so as to be able to slide on a part integral with the        seat portion and    -   immobilizable in a desired position with respect to this same        part,

a first extendable/retractable member being fastened, on the one hand,to the end of said first element opposite the end which is integral withthe back rest and, on the other hand, to the end of said second elementwhich is opposite the axis of rotation.

By virtue of this arrangement, as will be explained below, the back restrotation support can be moved in translation with respect to the seatportion.

In a preferred embodiment, the first extendable/retractable member is agas spring, i.e. an element with a hydro-pneumatic structure having acylinder and a piston, making it possible to pivot the back rest andcounterbalance the movement at a controlled speed, simply under theeffect of the user's upper torso pressing on the back rest.

Since the force of the user's pressing depends on the latter's weight,it is thus convenient to be able to adjust the gas spring.

To this end, its point of fastening to said back rest rotation supportis adjustable along said support.

Thus, the length of travel of the gas spring piston and, hence, itsresistance can be set as desired.

The seat portion sliding support advantageously comprises a stoplimiting the pivoting of the back rest with respect to the seat portion.

As stated above, the seat portion sliding support slides with respect toa part integral with the seat portion and is immobilizable with respectto this same part. The back rest rotation support and the seat portionsliding support are integral via the axis of rotation, and therefore theback rest rotation support also slides with respect to the part integralwith the seat portion and, as a result, the distance between the backrest and the free edge of the seat portion can be adjusted (in otherwords, the depth of the seat portion can be adjusted).

In adjustable seats, such as the seats in motor vehicles and airplanes,the backrest may be adjusted with respect to the general plane of theseat portion, which itself remains fixed. Seats are also known in whichthe rearward adjustment of the back rest causes the seat portion to tiltupward, and vice versa.

For improved comfort, it would however be desirable if, in the sameseat, not only the angle between the back rest and the seat portioncould be modified at will but also if the angle between the generalplane of the seat portion and the floor could also be modified, and ifthese two modifications could be independent of one another.

To this end, the seat according to the invention also comprises a seatportion support that rests directly or indirectly on the floor and thisseat portion support has a point of fastening for one of the ends of asecond extendable/retractable member whose other end is fastened to theseat portion.

This second extendable/retractable member may be a pneumatic jack or anelectric jack.

It is thus possible to tilt the back rest and the seat portionindependently of one another.

In a preferred embodiment of the invention, the seat is a relaxationarmchair and, to this end, it also comprises a leg rest.

Since it is important, here again, that the leg rest can be operatedindependently of the adjustment of the back rest and of the adjustmentof the seat portion, said leg rest has a point of fastening for one ofthe ends of a third extendable/retractable member whose other end isfastened to the seat portion.

This third extendable/retractable member may be a pneumatic jack or anelectric jack.

Thus, the first, second and third extendable/retractable membersfunction independently of one another.

A better understanding of the invention will be obtained from readingthe following description provided with reference to the attacheddrawings, in which:

FIGS. 1 a-1 c schematically show the respective planes of the three maincomponents (seat portion, back rest and leg rest) of a relaxationarmchair according to the invention and FIGS. 1 d-1 f schematically showthree possible depths of the seat portion according to the invention;

FIG. 2 is a schematic view of the installation of the threeextendable/retractable control members;

FIG. 3 is a detail view of the region of hinging between the back restand the seat portion and

FIG. 4 is a detail view of the hinge system of FIG. 3, seen from therear of the seat (arrow F in FIG. 3).

Referring to FIGS. 1 a-1 c, these show the positions occupied by theplanes of the seat 1, back rest 2 and leg rest 3, in the “sitting”position (FIG. 1 a), relaxation position (FIG. 1 b) and “zero gravity”position (heart lower than leg rest) (FIG. 1 c), respectively.

The seat portion 1 makes, with the back rest 2, an angle α which isvariable (α1<α2<α3) and, with the leg rest 3, an angle β which is alsovariable (β1<β2<β3), and α varies independently of β.

The three planes (plane of the seat portion 1, plane of the back rest 2and plane of the leg rest 3) can be moved independently of one another.

To this end, as shown by FIG. 2, three operating members are provided.

More specifically, the seat portion 1 is adjusted with respect to thefloor using a pneumatic jack 4 which bears, on the one hand, on saidseat portion 1 and, on the other hand, on a seat portion support 5resting on the floor; the back rest 2 is adjusted with respect to theseat portion 1 using a gas spring 6 which bears, on the one hand, onsaid seat portion 1 and, on the other hand, on a part 10 attached to theback rest 2; and the leg rest 3 is tilted with respect to the seatportion 1 using a pneumatic jack 7 which bears, on the one hand, on saidseat portion 1 and, on the other hand, on said leg rest. The gas spring6 is actuated, in one direction, simply by the user's upper torsopressing against the back rest 2 and, in the other direction, simply bythe user raising his back off the back rest and, if necessary, bearingon the arm rests (not shown). Note that the back rest 2 returnsautomatically since, when the user reclines by pressing with his uppertorso, the gas in the gas spring is compressed and, once the pressure isreleased, the gas expands. The pneumatic jacks 4 and 7 are actuated,entirely conventionally, by a push button. The pneumatic jacks 4 and 7could be replaced by electric jacks, keeping the gas spring 6 foroperating the back rest 2, or alternatively the gas spring 6 coulditself also be replaced by an electric jack.

Note that the seat portion 1 pivots about the point P. The seat portionsupport 5 has heightwise-adjustable legs.

The leg rest 3 incorporated in the armchair according to the inventionmay have the structure described in EP 1 099 396, i.e. an extendable andretractable structure, with little wheels in permanent contact with thefloor; thanks to these little wheels, extension only has to beinitiated, most of the extension movement taking place simply under theeffect of gravity.

Referring to FIG. 3, this shows in detail the region of hinging betweenthe seat portion 1 and the back rest 2, on one of the side faces of theseat, a symmetrical assembly being located on the other side face. Thereference 8 denotes a part integral with the back rest and the reference9 denotes a part integral with the seat portion. The hinge systemcomprises a first element 10, the “back rest rotation support”, and asecond element 11, the “seat portion sliding support”, the elements 10and 11 being joined by an axis of rotation 12.

As can be seen, the element 10 has roughly the shape of a bicorn hat,lying vertically, with the axis of rotation 12 passing through itapproximately at its center. At one of its ends, the element 10 isassembled fixedly to the part 8 integral with the back rest and, at itsother end, the element 10 has a point of fastening 13 for the rod 14 ofthe piston of the gas spring 6 whose cylinder 15 is fastened at 16 tothe second element 11. An adjustment screw 17 is provided for moving thepoint of fastening 13 and hence increasing or reducing the length oftravel of the piston of the gas spring 6.

A stop 18 limits the pivoting of the element 10 and hence of the backrest 2.

As can be seen more clearly in FIG. 4, the element 11 comprisesadjustment holes such as 19, which face slots such as 20 made in thepart 9, in such a way that the relative position of the element 11 andof the part 9 can be modified in translation by sliding and fixed in thedesired position by screwing in bolts, such as 21, which pass throughboth a hole 19 and a slot 20.

This assembly thus makes it possible to regulate both the control of thereclining of the back rest as a function of the weight of the user (byadjusting the level of the point of fastening 13) and that of the depthof the seat portion (by adjusting the relative position of the element11 and of the part 9).

The result of adjusting the depth of the seat portion is shownschematically by FIGS. 1 d-1 f. FIG. 1 d is identical to FIG. 1 a andshows a maximum seat portion depth P1, the base of the back rest 2adjoining the rear edge of the seat portion 1. FIG. 1 e shows a shorterseat portion depth P2<P1 due to relative movement between the back rest2 and the seat portion 1, the angles α1 and β1 remaining the same, andfigure if shows an even shorter seat portion depth P3<P2<P1 due torelative movement between the back rest 2 and the seat portion 1, theangles α1 and β1 always remaining the same. Note that the threepositions illustrated are merely three examples, any intermediateposition being possible, and that it is possible to modify the seatportion depth whatever the angles α and β.

Obviously, these adjustments, which require the use of tools, willgenerally be made on installation, depending on the person for whom thechair is intended. Thus, the same household may have two exactlyidentical chairs, except that one is adjusted for a short person ofslight build and the other for a tall, heavy person.

1-10. (canceled)
 11. A seat of the type comprising a seat portion and aback rest, hinged to one another about an axis of rotation, said hingingbeing achieved in the form of a pair of means located on either side ofthe seat about a plane of symmetry passing through the back rest and theseat portion, each of said means consisting of, on the one hand, a firstelement, forming a back rest rotation support, through which said axisof rotation passes and one end of which is integral with said back rest,and, on the other hand, a second element, wherein said second element isa part which is separate from the seat portion, integral with said firstelement via said axis of rotation which passes through said secondelement near one of its ends and said first element, mounted so as to beable to slide on a part integral with the seat portion and immobilizablein a desired position with respect to this same part, a firstextendable/retractable member being fastened, on the one hand, to theend of said first element opposite the end which is integral with theback rest and, on the other hand, to the end of said second elementwhich is opposite the axis of rotation.
 12. The seat as claimed in claim11, wherein said first extendable/retractable member is a gas spring.13. The seat as claimed in claim 11, wherein the point of fastening ofsaid first extendable/retractable member to said back rest rotationsupport is adjustable along said support.
 14. The seat as claimed inclaim 11, wherein said seat portion sliding support comprises a stoplimiting the pivoting of the back rest with respect to the seat portion.15. The seat as claimed in claim 11, also comprising a seat portionsupport, wherein this seat portion support has a point of fastening forone of the ends of a second extendable/retractable member whose otherend is fastened to said seat portion.
 16. The seat as claimed in claim11, also comprising a seat portion support, wherein this seat portionsupport has a point of fastening for one of the ends of a secondextendable/retractable member whose other end is fastened to said seatportion, wherein the first and second extendable/retractable membersfunction independently of one another.
 17. The seat as claimed in claim11, also comprising a leg rest, wherein said leg rest has a point offastening for one of the ends of a third extendable/retractable memberwhose other end is fastened to said seat portion.
 18. The seat asclaimed in claim 11, also comprising a seat portion support, this seatportion support having a point of fastening for one of the ends of asecond extendable/retractable member whose other end is fastened to saidseat portion, the first and second extendable/retractable membersfunctioning independently of one another a leg rest, said leg resthaving a point of fastening for one of the ends of a thirdextendable/retractable member whose other end is fastened to said seatportion, wherein the first, second and third extendable/retractablemembers function independently of one another.
 19. The seat as claimedin claim 15, wherein said second extendable/retractable member is apneumatic jack or an electric jack.
 20. The seat as claimed in claim 17,wherein said third extendable/retractable member is a pneumatic jack oran electric jack.
 21. The seat as claimed in claim 11, wherein saidfirst extendable/retractable member is an electric jack.